Integrated Space-Division Multiplexer for Application to Data Center Networks

The prospect of creating integrated space-division multiplexing (SDM) on a chip, utilizing the orthogonal degrees of freedom of numerous guided spatial modes in a multimode waveguide, promises a substantial reduction in the cost, complexity, and scalability of networking systems by augmenting or replacing the commonly used approach of wavelength-division multiplexing (WDM). As a demonstration of the SDM approach, we introduce and experimentally characterize a periodically nanostructured resonant coupler integrated with a multimode waveguide that selectively transfers energy between arbitrary waveguide modes. Compared to alternative schemes, this device possesses advantages in terms of packing density, control of operating bandwidth, tunability to operate with numerous orthogonal spatial modes, and support of a large number of switching ports.